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send/recv doesn't use zil?

PostPosted: Fri Jun 02, 2017 2:24 am
by tangles
Hi,

Am pushing a dataset to a raidz that has a log device and it's been zero IO the whole time...

Code: Select all
                                                  capacity     operations     bandwidth
pool                                            alloc   free   read  write   read  write
----------------------------------------------  -----  -----  -----  -----  -----  -----
Image                                            197G  35.3G    612      0  75.5M      0
  mirror                                         197G  35.3G    612      0  75.5M      0
    media-F04E4AE7-BF29-A34B-BC35-AACFE52FB20F      -      -    301      0  37.0M      0
    media-D640E788-75F1-894B-8713-0CBED2B60DE0      -      -    311      0  38.6M      0
----------------------------------------------  -----  -----  -----  -----  -----  -----
ztank                                           14.4T  7.34T      2  2.05K  4.48K   179M
  raidz1                                        7.20T  3.67T      0  1.08K    509  90.5M
    media-848CD0BD-0CA6-6646-AA0D-568DBF170D2D      -      -      0    360      0  29.9M
    media-8BDA1C4F-91B9-9F47-B80B-91A283275F31      -      -      0    372    509  30.6M
    media-4A8578E6-F78C-894D-911C-0070E39BD5FD      -      -      0    371      0  30.0M
  raidz1                                        7.20T  3.67T      1    997  3.98K  88.7M
    media-770994C7-11EC-D844-9BAF-CF778B5DADDD      -      -      0    342      0  30.7M
    media-B79A1F7B-E003-3049-BA89-58BA751520A6      -      -      0    308  1.99K  27.0M
    media-C483C925-A204-3F4C-B22D-01B88E04A1C4      -      -      0    345  1.99K  30.9M
logs                                                -      -      -      -      -      -
  media-A6219DF0-7A34-CE4C-93F1-58B8FCD39903     564K   112G      0      0      0      0
----------------------------------------------  -----  -----  -----  -----  -----  -----


Just curious for those who peak at the code whether this is by what's pushed to us by ZOL/other or whether it's occurred within the macOS port?

Re: send/recv doesn't use zil?

PostPosted: Sat Jun 03, 2017 12:43 pm
by Brendon
Hi,

My suggestion would be that you install an Illumos variant in a VM and repeat your test.

Cheers
Brendon

Re: send/recv doesn't use zil?

PostPosted: Tue Jun 06, 2017 6:38 pm
by lundman
slog is used in synced writes, which is only used depending on method you used to get the data. zfs recv does generally not use slog as data come in large serial data with transaction groups. I do not believe rsync does either, but I have noticed some "tar" will sync writes by calling fsync(). Mail delivery programs, sendmail/postfix/dovecot will also.